// Copyright 2013 Hans Wolff
//
// Source: https://gist.github.com/hanswolff/7926751
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.


[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.DocumentationRules", "*", Justification = "Third Party Library Code")]
[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.OrderingRules", "*", Justification = "Third Party Library Code")]
[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.LayoutRules", "*", Justification = "Third Party Library Code")]
[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "*", Justification = "Third Party Library Code")]
[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.ReadabilityRules", "*", Justification = "Third Party Library Code")]
[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "*", Justification = "Third Party Library Code")]
[module: System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.SpacingRules", "*", Justification = "Third Party Library Code")]
namespace NEventSocket.Util
{
    using System.Threading;

    /// <summary>
    /// Interlocked support for boolean values
    /// </summary>
    internal class InterlockedBoolean
    {
        private int _value;

        /// <summary>
        /// Current value
        /// </summary>
        public bool Value
        {
            get { return _value == 1; }
        }

        /// <summary>
        /// Initializes a new instance of <see cref="T:InterlockedBoolean"/>
        /// </summary>
        /// <param name="initialValue">initial value</param>
        public InterlockedBoolean(bool initialValue = false)
        {
            _value = initialValue ? 1 : 0;
        }

        /// <summary>
        /// Sets a new value
        /// </summary>
        /// <param name="newValue">new value</param>
        /// <returns>the original value before any operation was performed</returns>
        public bool Set(bool newValue)
        {
            var oldValue = Interlocked.Exchange(ref _value, newValue ? 1 : 0);
            return oldValue == 1;
        }

        /// <summary>
        /// Compares the current value and the comparand for equality and, if they are equal, 
        /// replaces the current value with the new value in an atomic/thread-safe operation.
        /// </summary>
        /// <param name="newValue">new value</param>
        /// <param name="comparand">value to compare the current value with</param>
        /// <returns>the original value before any operation was performed</returns>
        public bool CompareExchange(bool newValue, bool comparand)
        {
            var oldValue = Interlocked.CompareExchange(ref _value, newValue ? 1 : 0, comparand ? 1 : 0);
            return oldValue == 1;
        }
    }

    internal static class InterlockedBooleanExtensions
    {
        internal static bool EnsureCalledOnce(this InterlockedBoolean interlockedBoolean)
        {
            return interlockedBoolean.CompareExchange(true, false);
        }
    }
}
